Optic pathway gliomas in children: prognostic factors, response assessment, role of carboplatin and vincristine chemotherapy regime

Abstract

Low grade gliomas (LGG) constitute 35-40% of all primary central nervous system (CNS) tumors in children, at least 10-12% of them affecting the optic pathway. The complexity of the localization and predominantly the diffuse type of growth of these tumors make the neurosurgical treatment not appropriate in most cases, which requires conservative treatment. Objective: to analyze the results of carboplatin and vincristine chemotherapy (CT) regime in children with optic pathway gliomas (OPG). The study was approved by the Independent Ethics Committee of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology. In the study was included patients registered at the Burdenko Neurosurgery Institute from January 1, 2003 till December 31, 2015 with optic pathway glioma from 0 to 18 years old that were treated with combined carboplatin and vincristine chemotherapy. All patients were divided into 2 groups: the first group included patients who had newly diagnosed OPG (group 1), the second group included patients with OPG with radiological progression following observation times (group 2). Evaluation of the response to treatment was carried out on the 24th week and after completion of treatment by delineation of each slice of the MRI images in OsiriX MD software (© Pixmeo Sari, Switzerland) with subsequent automatic volume calculation. Results: 104 patients were included in the analysis. 69 children were included to group 1, 35 patients in group 2. 60% of patients were boys, about a third of children were less than 18 months old, 17% of patients had Neurofibromatosis type I, 24% of patients had diencephalic cachexia. A biopsy of the tumor was performed in 76% of the patients, 54% of the patients had a piloid astrocytoma and 23% had a pilomixoid astrocytoma. The progression after the start of the chemotherapy was in 30 (28.9%) patients. 5-year event free survival (EFS) and overall survival (OS) were 58 ± 6% and 97 ± 2%, respectively. 5-year EFS was not statistically significantly different in patients of groups 1 and 2. According to our data, the age, histology of the tumor, the response to the 24th week of CT are independent prognostic factors.